A source of human tissues has been secured which provides over 50 pairs of eyes per year with postmortem times under one hour. The retina and pigment epithelium from these tissues will be used for cell biological studies. The overall goal of this program is to identify the unique cell biological features of the human retina, both spatially and temporally which may underlie some of the basic processes which lead to lesions in the retina in response to inherited retinal diseases such as retinitis pigmentosa or macular degeneration. Specific aims of this study are to evaluate foveal versus peripheral retina in the synthesis of IRBP. Comparisons will be made of peripheral versus foveal cones in the synthesis of a glycoprotein which labels with galactose and is transported to the cone pedicle. An evaluation will be made of the ability of the fovea and peripherial retina to synthesize melatonin as well as to establish the regional distribution of HIOMT immunoreactivity. In addition, comparisons will be made of rods versus cones in the peripheral retina and foveal cones versus peripheral cones with respect to the endocytotic capabilities of the inner segments of these photoreceptor types using horseradish peroxidase, dextran and 125I-IRBP as tracers. The pigment epithelium from these donor eyes will be utilized to evaluate differences in the synthetic capabilities of this epithelium in submacular versus peripheral regions. Specific emphasis will be placed on components of the interphotoreceptor matrix which are synthesized by the pigment epithelial cells and secreted from their apical surface. Retinal tissues will also be utilized for continuation of studies on neurotransmitters in the inner retina with emphasis on GABA and acetylcholine. Techniques used in this project will include organ culture, radioactive tracers, polyacrylamide gel electrophoresis, fluorography, chromatography, immunocytochemistry, autoradiography and electron microscopy.